readFromDB<-function(lower=1, upper=1) {
    if (lower==1) lower="0000-01-01 00:00:00"
    if (upper==1) upper="9999-12-31 23:59:59" # Warning: Y10K bug.
    query=sprintf("select * from data where dateTime>datetime('%s') and dateTime<datetime('%s')",
            lower, upper)
    print(paste("...", query))
    data = dbGetQuery(con, query)
    data$dateTime = as.POSIXlt(data$dateTime)
    print(paste("...", "Read from DB.")) 
    return(data)
}
